Making a datapack containing any feature (i.e. any file in the configured_feature and placed_feature folders) will make that feature disappear from the world, unless the biomes folder is also present in the datapack. Also, it seems that both configured_feature and placed_feature must be present. On 1.17 you could have a datapack containing only some edited file from configured_feature, and it would work correctly.

I attach two datapacks, both contain only unedited files copied from the newest (1.18 pre1) vanilla_worldgen package. One has only some placed_feature configs (trees_*.json), and makes almost all trees disappear. The second has also the files from configured_feature (trees_*.json) and all the biomes, and it works correctly, like vanilla.